Novel Polylactide‐Based Release Systems for Local Antibiotic Therapies

Antibiotic delivery systems based on biodegradable polymers have found considerable interest for the local therapy of bone infections. In this study polylactide based polymer and composite delivery systems for the release of gentamicin have been fabricated from poly‐L‐lactides and a poly(L‐lactide‐co‐D,L‐lactide) as well as biodegradable inorganic fillers (calcium hydrogen phosphate, calcium sulfate dihydrate). The in vitro release profiles of the polymer delivery systems were characterized by an initial burst release followed by a sustained release of small gentamicin amounts up to 3 weeks. In the composite delivery systems a loss of retardation was observed with an increasing content of inorganic filler material. It was found that the in situ complex formation of gentamicin by adding defined amounts of sodium dodecyl sulfate represents a valuable tool to overcome this problem and to modulate the release profile of the delivery systems in a wide range. Under in vitro conditions, calcium sulfate dihydrate containing delivery systems are rapidly degraded in aqueous medium within several months. Based on these results, the developed composite delivery systems are promising candidates for the efficient treatment of bone infections.